DiffAlgorithms: Open Repository in try-with-resource

Change-Id: I67cb486283213f8aa964333533c55966518baa36
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>

org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/DiffAlgorithms.java

@@ -160,11 +160,8 @@ class DiffAlgorithms extends TextBuiltin {
 			else
 				rb.findGitDir(dir);
 
-			Repository repo = rb.build();
-			try {
+			try (Repository repo = rb.build()) {
 				run(repo);
-			} finally {
-				repo.close();
 			}
 		}
 	}